title: The rate and pattern of bcl-2 and cytokeratin 15 expression in trichoepithelioma and nodular Basal cell carcinoma: a comparative study.
abstract: BACKGROUND
  Histopathological evaluations can differentiate between clinically resembling trichoepithelioma (TE) and basal cell carcinoma (BCC) unless the biopsy specimens are small or superficial. Previous studies used immunohistochemical evaluation for Bcl-2 and cytokeratin 15 (CK15), in attempts to differentiate between these two entities, with heterogeneous findings.
  
  
  OBJECTIVE
  This study intended to compare the rate and patterns of Bcl-2 and CK15 expressions between specimens of TE and nodular BCC.
  
  
  METHODS
  Case-series including formalin-fixed, paraffin-embedded cutaneous biopsies.
  
  
  METHODS
  Twenty-two BCC and 12 TE specimens were stained for Bcl-2 and CK15 and examined microscopically. The rate and patterns of expressions were compared between the two groups.
  
  
  METHODS
  Statistical analysis was performed using the statistical software (SPSS version 16.0; SPSS Inc., Chicago, IL, USA), Pearson Chi-square, or Fisher's exact tests, wherever appropriate.
  
  
  RESULTS
  The two groups were comparable for the expression rate and patterns of Bcl-2 (86.4%: 5 central, 14 diffuse in BCC vs. 83.3%: 2 central, 8 diffuse in TE; P = 0.59 and 0.54 for rate and pattern, respectively). The rate of CK15 expression was significantly higher in TE specimens (66.7%: 4 central, 3 diffuse, 1 peripheral vs. 4.5%: 1 central; P < 0.001). The positive likelihood ratio in distinguishing the two neoplasms was 14.7 (95% confidence interval: 2.1-103.7).
  
  
  CONCLUSIONS
  CK15 but not Bcl-2 staining may help in differentiating between BCC and TE even in BCCs with follicular differentiation.
authors.affiliation: Loghman Hakim Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Shahram
authors.initials: S
authors.lastname: Sabeti
authors.forename: Farhad
authors.initials: F
authors.lastname: Malekzad
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Ashayer
authors.forename: Rohollah F
authors.initials: RF
authors.lastname: Fouladi
authors.forename: Kambiz K
authors.initials: KK
authors.lastname: Hesari
authors.forename: Mihan P
authors.initials: MP
authors.lastname: Toutkaboni
authors.forename: Shima
authors.initials: S
authors.lastname: Younespour
keywords: Bcl-2; cytokeratin 15; nodular basal cell carcinoma; trichoepithelioma